6. Total phenolic content (TPC)
The Folin-ciocalteau micro method of Waterhouse (n.d.) was used. Sixty μl of the extract was diluted with deionized water to 4.8 ml, and 300 μl Folin-ciocalteau reagent was added and shaken. After 8 min, 900 μl of a 20% sodium carbonate was added with mixing. Leave the solution at 40oC for 30 min before reading the absorbance at 765 nm. Gallic acid (0-50 μg) was
used as a standard, and results were reported as mg gallic equivalent per gram of dry weight.